the X3 has a completed port, but my web search on this model doesn't turn anything up. Since xDuoo seems to be cagey about letting hardware specs out, this will likely take some time to finish ... or even start.

The X3 was just through here at about the same price-point, wasn't it? I'd expect that's the one you want to keep your eyes out for. A long-term-review I just read about the X3 said that xDuoo had only released one firmware update, and it didn't fix that user's problems with the device, but rockbox fixed all of them so that was fine by him...but it does reveal xDuoo's attitude towards their devices, if long term maintenance doesn't get much of a budget from them.